mat3x3:
	mat[0]= cos(y)cos(z) = 1/2 (cos(y-z)+cos(y+z))
	mat[1]= -cos(y)sin(z) = 1/2 (sin(y-z)-sin(y+z))
	mat[2]= sin(y)

	mat[3]= sin(x)sin(y)cos(z)+cos(x)sin(z)
=1/4 (cos(x-y-z)-cos(x+y-z)+cos(x-y+z)-cos(x+y+z)-2 sin(x-z)+2 sin(x+z))
	mat[4]=
	mat[5]= -sin(x)cos(y) = 1/2 (-sin(x-y)-sin(x+y))

	mat[6]=
	mat[7]=
	mat[8]=cos(x)cos(y) = 1/2 (cos(x-y)+cos(x+y))